124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
#include "adxl345.h"
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#include <stddef.h>
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#define ADXL345_REG_DEVID 0x00
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#define ADXL345_REG_BW_RATE 0x2C
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#define ADXL345_REG_POWER_CTL 0x2D
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#define ADXL345_REG_DATA_FORMAT 0x31
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#define ADXL345_REG_DATAX0 0x32
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#define ADXL345_DEVID_VALUE 0xE5
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#define ADXL345_BW_RATE_100_HZ 0x0A
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#define ADXL345_POWER_MEASURE 0x08
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#define ADXL345_FORMAT_FULL_8G 0x0A
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#define ADXL345_TIMEOUT_MS 100
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static esp_err_t read_registers(i2c_master_dev_handle_t device, uint8_t start_register,
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uint8_t *data, size_t length)
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{
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return i2c_master_transmit_receive(device, &start_register, 1, data, length,
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ADXL345_TIMEOUT_MS);
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}
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static esp_err_t write_register(i2c_master_dev_handle_t device, uint8_t reg, uint8_t value)
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{
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const uint8_t bytes[] = {reg, value};
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return i2c_master_transmit(device, bytes, sizeof(bytes), ADXL345_TIMEOUT_MS);
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}
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static esp_err_t verify_register(i2c_master_dev_handle_t device, uint8_t reg, uint8_t expected)
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{
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uint8_t actual = 0;
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esp_err_t err = read_registers(device, reg, &actual, 1);
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if (err != ESP_OK) {
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return err;
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}
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return actual == expected ? ESP_OK : ESP_ERR_INVALID_RESPONSE;
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}
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esp_err_t adxl345_init(adxl345_t *sensor, i2c_master_bus_handle_t bus, uint32_t bus_speed_hz)
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{
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if (sensor == NULL || bus == NULL) {
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return ESP_ERR_INVALID_ARG;
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}
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*sensor = (adxl345_t){0};
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static const uint8_t candidate_addresses[] = {0x53, 0x1D};
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for (size_t i = 0; i < sizeof(candidate_addresses); ++i) {
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const i2c_device_config_t config = {
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.dev_addr_length = I2C_ADDR_BIT_LEN_7,
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.device_address = candidate_addresses[i],
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.scl_speed_hz = bus_speed_hz,
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};
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i2c_master_dev_handle_t device = NULL;
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esp_err_t err = i2c_master_bus_add_device(bus, &config, &device);
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if (err != ESP_OK) {
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return err;
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}
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uint8_t device_id = 0;
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err = read_registers(device, ADXL345_REG_DEVID, &device_id, 1);
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if (err == ESP_OK && device_id == ADXL345_DEVID_VALUE) {
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sensor->device = device;
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sensor->address = candidate_addresses[i];
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break;
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}
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i2c_master_bus_rm_device(device);
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}
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if (sensor->device == NULL) {
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return ESP_ERR_NOT_FOUND;
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}
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// Configure while in standby, then enter measurement mode.
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esp_err_t err = write_register(sensor->device, ADXL345_REG_POWER_CTL, 0x00);
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if (err == ESP_OK) {
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err = write_register(sensor->device, ADXL345_REG_DATA_FORMAT, ADXL345_FORMAT_FULL_8G);
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}
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if (err == ESP_OK) {
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err = write_register(sensor->device, ADXL345_REG_BW_RATE, ADXL345_BW_RATE_100_HZ);
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}
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if (err == ESP_OK) {
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err = write_register(sensor->device, ADXL345_REG_POWER_CTL, ADXL345_POWER_MEASURE);
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}
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if (err == ESP_OK) {
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err = verify_register(sensor->device, ADXL345_REG_DATA_FORMAT, ADXL345_FORMAT_FULL_8G);
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}
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if (err == ESP_OK) {
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err = verify_register(sensor->device, ADXL345_REG_BW_RATE, ADXL345_BW_RATE_100_HZ);
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}
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if (err == ESP_OK) {
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err = verify_register(sensor->device, ADXL345_REG_POWER_CTL, ADXL345_POWER_MEASURE);
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}
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return err;
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}
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esp_err_t adxl345_read_raw(const adxl345_t *sensor, adxl345_sample_t *sample)
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{
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if (sensor == NULL || sensor->device == NULL || sample == NULL) {
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return ESP_ERR_INVALID_ARG;
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}
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uint8_t data[6] = {0};
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esp_err_t err = read_registers(sensor->device, ADXL345_REG_DATAX0, data, sizeof(data));
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if (err != ESP_OK) {
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return err;
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}
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sample->x = (int16_t)((uint16_t)data[0] | ((uint16_t)data[1] << 8));
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sample->y = (int16_t)((uint16_t)data[2] | ((uint16_t)data[3] << 8));
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sample->z = (int16_t)((uint16_t)data[4] | ((uint16_t)data[5] << 8));
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return ESP_OK;
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}
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uint8_t adxl345_address(const adxl345_t *sensor)
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{
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return sensor != NULL ? sensor->address : 0;
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}
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